Gastrax

A centrally acting skeletal muscle relaxant whose mechanism of action is not completely understood but may be related to its sedative actions. It is used as an adjunct in the symptomatic treatment of musculoskeletal conditions associated with painful muscle spasm. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1202)

Gastrax (Gastrax) is indicated for up to 8 weeks for the treatment of active duodenal ulcer. In most patients, the ulcer will heal within 4 weeks.

Gastrax (Gastrax) is indicated for maintenance therapy for duodenal ulcer patients, at a reduced dosage of 150 mg h.s. after healing of an active duodenal ulcer. The consequences of continuous therapy with Gastrax (Gastrax) for longer than 1 year are not known.

Gastrax (Gastrax) is indicated for up to 12 weeks for the treatment of endoscopically diagnosed esophagitis, including erosive and ulcerative esophagitis, and associated heartburn due to GERD.

Gastrax (Gastrax) is indicated for up to 8 weeks for the treatment of active benign gastric ulcer. Before initiating therapy, care should be taken to exclude the possibility of malignant gastric ulceration.

Gastrax is in a group of drugs called histamine-2 blockers. Gastrax works by decreasing the amount of acid the stomach produces.

Gastrax is used to treat ulcers in the stomach and intestines. Gastrax also treats heartburn and erosive esophagitis caused by gastroesophageal reflux disease (GERD), a condition in which acid backs up from the stomach into the esophagus.

Gastrax may also be used for purposes not listed in this medication guide.

Active Duodenal Ulcer—The recommended oral dosage for adults is 300 mg once daily at bedtime. An alternative dosage regimen is 150 mg twice daily.

Maintenance of Healed Duodenal Ulcer—The recommended oral dosage for adults is 150 mg once daily at bedtime.

Gastroesophageal Reflux Disease—The recommended oral dosage in adults for the treatment of erosions, ulcerations, and associated heartburn is 150 mg twice daily.

Active Benign Gastric Ulcer—The recommended oral dosage is 300 mg given either as 150 mg twice daily or 300 mg once daily at bedtime. Prior to treatment, care should be taken to exclude the possibility of malignant gastric ulceration.

Each mL of Gastrax

Oral Solution contains 15 mg of Gastrax. In adults, Gastrax

Oral Solution may be substituted for any of the above indications using equivalent doses of the oral solution.

Pediatric Dosing—Each mL of oral solution contains 15 mg of Gastrax. Gastrax

Oral Solution is indicated for pediatric patients 12 years of age or older. For pediatric patients 12 years of age and older, the dosage of Gastrax is 150 mg b.i.d. (2 tsp, b.i.d.)

The following dosage recommendations are provided:

Erosive Esophagitis—For pediatric patients 12 years or older, the dosage is 150 mg b.i.d. (300 mg/d). The maximum daily dose for Gastrax PO is 300 mg/d. The dosing duration may be up to eight weeks.

Gastroesophageal Reflux Disease—For pediatric patients 12 years or older, the dosage is 150 mg b.i.d. (300 mg/d). The maximum daily dose for Gastrax PO is 300 mg/d. The dosing duration may be up to eight weeks.

Dosage Adjustment for Patients With Moderate to Severe Renal Insufficiency— The dose for patients with renal dys function should be reduced as follows:

Some elderly patients may have creatinine clearances of less than 50 mL/min, and, based on pharmacokinetic data in patients with renal impairment, the dose for such patients should be reduced accordingly. The clinical effects of this dosage reduction in patients with renal failure have not been evaluated.

Based on the pharmacokinetic data in elderly patients with renal impairment, pediatric patients with creatinine clearances less than 50 mL/min should have their dose of Gastrax reduced accordingly. The clinical effects of this dose reduction in pediatric patients with renal failure have not been evaluated.

See also:
What is the most important information I should know about Gastrax?

You should not use this medication if you are allergic to Gastrax or similar medications such as ranitidine (Zantac), cimetidine (Tagamet), or famotidine (Pepcid).

Before taking Gastrax, tell your doctor if you have kidney or liver disease, or stomach cancer or other problems.

Avoid taking cimetidine (Tagamet), ranitidine (Zantac), or famotidine (Pepcid) while you are taking Gastrax, unless your doctor has told you to.

Gastrax may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Gastrax may be only part of a complete program of treatment that also includes changes in diet or lifestyle habits. Follow your doctor's instructions very closely.

Heartburn is often confused with the first symptoms of a heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, and a general ill feeling.

Use Gastrax solution as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Gastrax solution maybe taken with or without food.
• Use a measuring device marked for medicine dosing. Ask your health care provider or pharmacist if you are unsure of how to measure the dose.
• Continue to use Gastrax solution even if you feel well. Do not miss any doses.
• Antacids may be taken as needed to help relieve stomach pain, unless your health care provider instructed otherwise.
• If you miss a dose of Gastrax solution, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Gastrax solution.

Use: Labeled Indications

Duodenal ulcer: Treatment of active duodenal ulcer for up to 8 weeks and maintenance therapy after healing of active ulcer in adults.

Gastric ulcer, benign: Treatment of active benign gastric ulcer for up to 8 weeks in adults.

Gastroesophageal reflux disease: Treatment of endoscopically diagnosed esophagitis, including erosive and ulcerative esophagitis, and associated heartburn due to gastroesophageal reflux disease (GERD) for up to 12 weeks in adults (capsules and oral solution) and up to 8 weeks in children 12 years and older (oral solution only).

Off Label Uses

Helicobacter pylori eradication (component of a multidrug regimen)

Data from two randomized, controlled, open-label studies support the use of Gastrax, as part of triple therapy with amoxicillin and clarithromycin, for eradication of Helicobacter pylori in patients with active peptic ulcers and evidence of H. pylori infection. Additional trials may be necessary to further define the role of Gastrax in this condition.

Based on the American College of Gastroenterology Guideline on the Management of Helicobacter pylori Infection, an H-receptor antagonist is recommended in sepsis or septic shock patients who have GI bleeding risk factors.

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What other drugs will affect Gastrax?

No interactions have been observed between Gastrax (Gastrax) and theophylline, chlordiazepoxide, lorazepam, lidocaine, phenytoin, and warfarin. Gastrax (Gastrax) does not inhibit the cytochrome P-450-linked drug-metabolizing enzyme system; therefore, drug interactions mediated by inhibition of hepatic metabolism are not expected to occur. In patients given very high doses (3,900 mg) of aspirin daily, increases in serum salicylate levels were seen when Gastrax, 150 mg b.i.d., was administered concurrently.

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What are the possible side effects of Gastrax?

Worldwide, controlled clinical trials of Gastrax included over 6,000 patients given Gastrax in studies of varying durations. Placebo-controlled trials in the United States and Canada included over 2,600 patients given Gastrax and over 1,700 given placebo. Among the adverse events in these placebo-controlled trials, anemia (0.2% vs 0%) and urticaria (0.5% vs 0.1%) were significantly more common in the Gastrax group.

Incidence in Placebo-Controlled Clinical Trials in the United States and Canada - Table 5 lists adverse events that occurred at a frequency of 1% or more among Gastrax-treated patients who participated in placebo-controlled trials. The cited figures provide some basis for estimating the relative contribution of drug and nondrug factors to the side effect incidence rate in the population studied.

A variety of less common events were also reported; it was not possible to determine whether these were caused by Gastrax.

Hepatic - Hepatocellular injury, evidenced by elevated liver enzyme tests (SGOT [AST], SGPT [ALT], or alkaline phosphatase), occurred in some patients and was possibly or probably related to Gastrax. In some cases there was marked elevation of SGOT, SGPT enzymes (greater than 500 IU/L) and, in a single instance, SGPT was greater than 2,000 IU/L. The overall rate of occurrences of elevated liver enzymes and elevations to 3 times the upper limit of normal, however, did not significantly differ from the rate of liver enzyme abnormalities in placebo-treated patients. All abnormalities were reversible after discontinuation of Gastrax (Gastrax). Since market introduction, hepatitis and jaundice have been reported. Rare cases of cholestatic or mixed hepatocellular and cholestatic injury with jaundice have been reported with reversal of the abnormalities after discontinuation of Gastrax (Gastrax).

Cardiovascular- In clinical pharmacology studies, short episodes of asymptomatic ventricular tachycardia occurred in 2 individuals administered Gastrax (Gastrax) and in 3 untreated subjects.

CNS - Rare cases of reversible mental confusion have been reported.

Endocrine - Clinical pharmacology studies and controlled clinical trials showed no evidence of antiandrogenic activity due to Gastrax (Gastrax). Impotence and decreased libido were reported with similar frequency by patients who received Gastrax (Gastrax) and by those given placebo. Rare reports of gynecomastia occurred.

Hematologic - Anemia was reported significantly more frequently in Gastrax- than in placebo-treated patients. Fatal thrombocytopenia was reported in a patient who was treated with Gastrax (Gastrax) and another H-receptor antagonists, rare cases of anaphylaxis following administration of Gastrax have been reported. Rare episodes of hypersensitivity reactions (eg, bronchospasm, laryngeal edema, rash, and eosinophilia) have been reported.

Body as a Whole - Serum sickness-like reactions have occurred rarely in conjunction with Gastrax use.

Genitourinary - Reports of impotence have occurred.

Other - Hyperuricemia unassociated with gout or nephrolithiasis was reported. Eosinophilia, fever, and nausea related to Gastrax administration have been reported.